Machine for straightening metal bars



Dec. 6, 1932. H. M. GIVENS r 1,

MACHINE FOR STRAiGI-ITENING METAL BARS Filed Aug. 25, 1931 Arron/5K5. I

Patented Dec. 6, 1932 UNITED STATES nowAnn M. GIVENS, or ABInG'ron; PENNSYLVANIA MACHINE non STRAIGHTENING Murat: BARS" Application filed August 25,1931. Serial No. 559,216.

As is well known,'the straightening of metal bars, rods, etc., has been effected in ma- )chines of difl erent types allinvolving the subjection of the bar, while it is moving -lengthwise, to the action of opposingpressuresurfaces which first overbend and then straighten. it. Such machines are usually of two types 1st.. Those with a long series of upper and 19 lower rolls revolving on axes at right angles tothe bar being straightened, and which can befused to straighten bars ofany cross section if. appropriate grooves bercut in their circumferences. Y 2nd-Those having two or more long rolls with axes inparallel vertical planes but. opupositely inclined to the horizontal, through a smallangle, the bar to'be straightenedbeing l revolved and drawnlen'gthwise between them while resting upon a supporting guide beneath. This type of machine can straighten on-lyround bars ofrelatively large diameter. It is usual to havelone of these rolls concave in longitudinal outlinewhile. the other may be cylindrical or'convex. In some machines -'operating on'this principle the rolls, instead otbeing'fixed in position and'revolving the bar. between them, are carried in a cradle,'or cradles, and revolve around the bar.

In both these types of machines the bar is bent backand forth between the rolls, in a vertical plane' only in the first type, but while -:beingrevolved in the second type,which' firstibend the bar regularly to a greater-degree than the initialpirregular bends, thus removing them, and finally remove theregular bends produced. 7 7 These machines workwell with material of low or moderate elastic-limit, but I have found it impossible with them to straighten bars of-small diameter and high elastic limit, ,becausethe centers on which the machines bend the bars are so far apart that the special bars spring enough to conform to the bends I given and then spring back again without having been permanently bent. In the case of the first type machine there is no remedy be- "cause the rolls, lying inthe plane of the bar, cannot be brought sufficiently near together to ,make short bends, their diameter preventdelivered straight and true.

. thattheaXis of eachis inclined relatively .to p that of the other. In the actual construction the axis of each roll is inclined to the-horiparallelism may be. more or less varied in some machines it is, ad ustable, anothers H fiXed.

2 and 3 and the foregoing descriptiom-taken in connection with Fig. 1, that such must be ing it, but Iha ve tounda novel way ofmaking. rolls for the second type oftmachjine which completely. accomplishes my" object andforms the subject -Ofijthis patent-application. M

I have found that by cutting a properly designed series ofcircumferential grooves in practically cylindricalrolls, with this type of machine one canbendthe bars between such Iclose centers that theirfelastic limit is exceeded, the necessary preliminary removal of existing bends accomplished .and the bars Rolls embodying iny invention are shown in the annexe'djdrawing, in-which-e 1] Fig. 1 is a plan view of the twojadja'cent halves ofeach 0t apair of straightening rolls.

Fig. 2 isa diagrammatic side View, and Fig. 3 an end'view, of the rolls, the desirable deviation of the rolls from parallelism being exaggerated in order more strikingly to illustrate thi'sfeature of the invention.

The two rolls a andb are mounted side by side. Inside view the'rolls are so positioned zontal about two degrees, but in opposite directions, as clearly'shown inFigs. 2 and 3. In Fig. 1-, in order that'the' "peripheral contours of the 'rolls'may be better illustrated, the two rolls are arranged with their axes parallel. The degree of deviation from' The peripheries of the two rolls re, adjustabiy spaced apart, the average'distance between them being least at their longitus dinal' centersand (due to their relative inclinati ons) gradually increasing towardtheir opposite extremities. This feature does not show in Fig.1, but it is apparent, from Figs.

the case. The dimensions of'thegrooves and ribs depend upon the diameter ofjthebars to be straightened, but one set of rolls will straighten barshavin a considerable ran e in diameter.

Each roll comprises alternating convex and concave circumferential surfaces, the concave circumferential surfaces of each roll being respectively opposite the convexcireumferential surfaces of the other roll. The convexities and concavities need not take the form of continuous and regular curves; For

example,'it is desirable that each roll shall comprise narrow sections 0 of true cyli-ndrical shape, alternating w th, convexo-concave.

sections (Z. Where actual curvaturejexists',

it should be-on' radii much'shorter than the radiusof the rolls, as indicated by the arrow g. The extreme front end of one roll 1 and the extreme rear end of the other roll :may each have a comparatively wide truly cylindrical" periphery" with a preferably roundedfextremity, as" indicated at. e: The

oppositeend of each roll has preferably a substantially narrower cylindrical periph- I cry, as indicated at f.

The two rolls have, preferably, approxi mately the same contour, but I have found it expedient to make. oneroll with its: ribs "of uniform diameter While, inthe case'of the other roll, the end ribs are of'relatively small diameter, the ribs' adj ace nt thereto of relatively large di anret'en andthe' two central ribs of intermediate diameter. The maxi.- mum differencein diameter will not usually exceedabout an eighth ofjanunchand no.

I attemptis made in the drawing to illustrate this slight differenca'which difference is not an essential feature, and may not, in all cases, be a desirable feature, of the invention. In

. any constructiom the longitudinal contour of one roll fromfront to rear closely resembles the longitudinal contour of: the other roll .from rear to front.

The bar to be straightened is, by action of. the'rolls, carried in the direction of their lengthwise extension by drivingthein in opposite directions. The means for supporting the bar during straightening are not shownas they. are those in common use and form no part of the invention. The action" of the rolls upon the bars isv p'erfectly to straighten them, 1

. The distancebetween the rolls is adjusted in accordance with the diameter of the bars to be 'straightened.

The rolls, instead of rotating, around fixed axe's,.may beheld in a frame and rotate about the bar.

Mechanism for so actuating the rolls, being known in the art, isfnot shown. What I claim is l i 1. A bar straightening machine comprising two rotatable rolls arranged side by side i so ' and' slightly spaced apart, each roll having a succession. of alternating approximately convexfand ,concave circumferential faces, the

concave circumferential surfaces of each roll being. substantially opposite the convex circumferential faces of the other roll, the axes of the two rolls, when the same are viewedin positely inclined,

inclined with respect to a horizontal plane.

3.. A bar straightening machine comprising two rotatable rolls arranged side by side and slightly apart,- each roll having a succession of alternating convex and conac'ave circum ferential faces, each of a number of said convex circumferential"surfaces comprising a eentralcylindrical surface, which isfopposite the central portion of a concave circumferential surface of the other roll,:therolls being adapted to be driven in opposite direc tions so as to revolve between them the bar to be straightened. I 4 9 0 4. A bar straightening machine compris ing two rolls positioned side byisi-des and spaced: somewhat. apart, the peripheryof each roll, along any radial pl'ane...ineludingwits axis, presenting awave-likecontour, thezcon it tour of each roll fromv front to rear'being sub- 'stanti-ally the same asthe contour'of theoth er roll from rear to front, both.- roll sabeing in clined to the horizontal but in; opposite directions.

5. A machine forstraightening bars comprising two rolls positioned side by side and spaced somewhat apart and adaptable to be rotated in'opposite directions, each. rollv comprisinga series of cylindrical sections alter-' t nating with a series of convexo-conc'ave sec-'- tions, the middle part. of the concavities of each roll being respectively'opposite cylindrical parts of the other roll-,lthe rolls. being op 6. A machine for-straightening bars comprising two rolls positioned side by side'and spaced somewhat apart and adaptable to be rotated in oppositedirections, each roll comif prising a series ofcylindrical sections alter-"" 1 nating with a series of convexo-concavesec tions, the middle part of the concavi-tiesof each roll being respectively opposite'cylindrical parts of the other roll, opposite extrem ities of each rollcomprising relatively wide and narrow cylindrical sections, the contour of each roll fro-m front to rear being approximately the same as the contour of, the other roll from rear to front, both rollsbeing in clined to the horizontal but in opposite directions..

7 Rolls for a machine for straightening metal bars, each rollhaving a series of circumferential convexities and concavitiesso positioned longitudinally as to be opposite a corresponding series of concavities and convexities in the other roll, the axes of the two rolls, when the same are viewed in side elevation, being inclined relatively to each other whereby a bar rotated between such rolls while passing between them longitudinally is bent back and forth to remove short kinks and is delivered straight. a

8. A bar straightening machine comprising two rotatable rolls arranged side by side and slightly spaced apart, each roll having a succession of alternating approximately convex and concave circumferential faces, the concave circumferential surfaces of each roll being substantially opposite the convex circumferential faces of the other roll, the rolls being so relatively positioned that when their axes are included in twoparallel planes, the projection of the axis of one roll on the plane of the other roll forms a slight angle with the axis of such other roll.

In testimony of which invention, I havehereunto set my hand, at Philadelphia, Pennsylvania, on this 19th day of August, 1931. HOWARD M. GIVENS. 

